Railway braking apparatus



Feb. 20, 1934. H. 1 BONE RAILWAY BRAKING APPARATUS 2 Sheets-Sheet l Filed Oct. 25, 1932 BY @Q1/@VWM HIJ' A TTORNE Y Feb. 20, 1934. BONE 1,947,638

RAILWAY BRAKING APPARATUS Filed Oct. 25, 1932 2 Sheets-Sheet 2 T0 fou/00 0F Fluid Pra/Pupa Hepbep L .30129.

1]]57 A TTORNE Y Patented Feb. 20, 1934 UNITED STATESv PATENT OFFICE RAILWAY BRAKING APPARATUS Application October 25, 1932. Serial No. 639,433

My invention relates to railway braking apparatus, and particularly to braking apparatus of the type comprising wheel engaging braking bars located beside a track rail, and movable toward and away from the rail into braking and non-braking positions. More particularly, my invention relates to apparatus of the type described in which the braking bars are arranged to be moved to their braking positions by a fluid pressure operated motor, and to be restored to their non-braking positions by suitable biasing means, such as gravity.

I will describe two forms of apparatus embodying my invention, and will then point out the i5 novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view, partly diagrammatic and partly cross-sectioned, illustrating one form of apparatus embodying my invention. Fig. 2 is a similar View showing a modiiied form of the apparatus illustrated in Fig.

l and also embodying my invention.

Similar reference characters refer to similar parts in both views.

Referring to the drawings, the reference character 1 designates one track rail of a stretch of railway track, which track rail, as here shown, is secured to a rail support 2 mounted on an adjacent pair of the usual crossties 3, only one crosstie being visible in the drawings. Associated with the rail 1 is a car retarder comprising two braking bars A1 and A2 located on opposite sides of rail l. Each of these braking bars comprises, as usual, a brake beam 4 and a brake shoe 5'.

The braking bars A1 and A2 are arranged to be moved toward and away from the rail 1 through the medium of a lever 6 which is pivotally mounted at one end on a pivot pin 8 carried by the rail support 2, and a lever '7 which is pivotally mounted intermediate its ends on the pivot pin 8. The e0 lever 6 is inclined upwardly and extends away from the rail 1 and is provided in its upper surface with a groove 6a which receives the braking bar A1. The one end 7a of the lever 7 is` likewise inclined upwardly and extends away from the rail l at the opposite side of the rail from the lever 6, and the other end 7b of the lever 7 is inclined downwardly and extends away from the rail 1 below the lever 6. The end 7a of the lever '7 is provided in its upper surface with a groove 7c, similar to the groove 6a in the lever 6, which groove receives the braking bar A2. The parts are so arranged and so proportioned that if the outer or free ends of the levers 6 and 7 are moved apart, the braking bars will be moved towardthe rails into their effective or braking positions.

When the brakingbars occupy their braking positions, the brake shoes will engage the opposite side faces of a car Wheel traversing rail 1', andA willretard the speed of the car.` The center of gravity'of the lever 6 and brakingl bar A1 is con- 00` siderably to the left of the pivot pin 8 so that this lever will normally tend to rotate in a counter-clockwise direction about the pivot pin. Similarly, the center of gravity of the lever 7 and braking. bar A2. is to the right of the pivot pin 8 6b so that this lever will normally tend to rotate in a clockwise direction about the pivot pin. It will be apparent, therefore, that when no force is applied to the free ends of the levers 6 and 7 to move them apart, the free ends of these levers will move toward each other, thereby movingthe braking bars to their ineffective or non-braking positions in which they are illustrated in the drawings.

The levers 6 and 7 are arranged to be moved 'fi apart by means of a fluid pressure motor M comprising a cylinder 9 containing a reciprocable piston 10 which is attached to the inner end of a piston rod 11. The cylinder 9 is pivotally connected with the free end or" the lever 6 by 80- means of trunnions 12 formed on the side of the cylinder and extending through bifurcations 13 formed on the lever 6, while the piston rod 11 is connected at its free end with the free end 7b of the lever 7 by means of an adjustable eyebolt 8l!-` 14 and a pivot pin 15. Fluid pressure may be admitted to the cylinder 9 between the-upper end of the cylinder and the piston 10f throughy an opening 16 which is threaded to receive a pipe 17. When uid pressure is admitted to the cylin- `v der 9 through the pipe 17 and opening 16, the piston 10 will be forced downwardly and the cylinder 9 upwardly, thereby separating the levers 6 and 7, and hence moving the braking bars toward their effective or braking positions. It will be obvious that when the braking bars are moved to their braking positions, they will exert a braking force which is proportional to the pressure of the iiuid supplied tothe cylinder 9.

The motor M is controlled bytwo magnet valves V1 and V2, each comprising a valve stem 18 biased to an upper position by means of a spring 19, and provided with a Winding 20 and an armature 21. When valve. Vlis energized', valve stem 18 of this valve moves downwardly against the bias exerted by the associated spring 19, and pipe 17 is then connected with-atmosphere through a port 22. Whenfvalve'Vf is'de'- energized, however, pipe 17 is disconnectedfrom atmosphere and is connected with a-pipe23f1eadlar manner,

ing to the valve V2. When valve V2 is energized, valve stem 18 of this valve moves downwardly, and connects the pipe 23 with a pipe 24 which is constantly supplied with fiuid pressure, usually air, from a suitable source not shown in the drawings, but when valve V2 is deenergized, as shown in the drawings, pipe 23 is disconnected from the pipe 24. It will be apparent, therefore, that when valve V1 is energized, the region of cylinder 9 of motor M between the piston 10 and the upper end of the cylinder is connected with atmosphere, so that the braking bars of the car retarder will then be held in their ineffective or non-braking positions by gravity. When, however, valve V1 is deenergized and valve V2 is energized, fluid pressure will be supplied to the upper end of cylinder 9 of motor M, thus causing the braking bars to move to their effective or braking positions.

The valves V are controlled in part by a plurality of pressure responsive devices P2040, B21-55, and P20410, each comprising a Bourdon tube 25 connected to the pipe 17, and hence subjected to the pressure of the fluid in the region of cylinder 9 between piston 10 and the upper end of the cylinder. Each Bourdon tube 25 controls two contacts 26-26a and 26-26b. The pressure responsive devices P20-2, 1245-55, and PTU-20 are so constructed and so adjusted that they will operate successively as the pressure in the region of cylinder 9 between the piston 10 and the upper end of the cylinder increases. For example, for all pressures below twenty pounds per square inch, the contact 26-26a of each of these devices is closed. If the pressure exceeds twenty pounds per square inch, however, contact 26-26a of device P2030 opens, and if the pressures exceeds thirty pounds per square inch, contact 26--26b of device P20-30 closes. In simithe pressure responsive devices 1245-55 and P10-8 are adjusted to open their contacts 26--26a at forty-five and seventy pounds per square inch, respectively, and to close their contacts 26-23b at fifty-five and eighty pounds per square inch, respectively. Of course, these specific pressures are not essential but are only mentioned for purposes of explanation.

The valves V are also controlled by means of a manually operable lever L which, as here shown, is capable of assuming ve positions, indicated by dotted lines in the drawings and designated by the reference characters 121-215, inclusive. The lever L controls a plurality of contacts, each designated by the reference character 27 with a distinguishing exponent corresponding to therposition of the lever in which the corresponding contact is closed. For example, contact 271 is closed in'the p1 position of the lever, contact 272 in the p2 position of the lever, etc.

Lever L will usually be located at a point remote from the braking apparatus, as in the control cabin of a classification yard car retarder system, and will be connected with the braking apparatus by means of line wires extending from the control cabin to the braking apparatus. As shown in the drawings, lever L occupies its p1 or off position, which is a position which it normally occupies when no cars are to be retarded, and all of the contacts of lever L, with the exception of contact 271, are therefore open. ValveV2 is therefore deenergized, but valve V1 is energized over a circuit which passes from a suitable source of current, here shown as a battery B, through wires 28, 29, 30, 31 and 32, contact 271 of lever L, line wire 33, wires 34, 35 and 36,

winding 20 of valve V1, and line wire 37 back to battery B. Since Valve V2 is deenergized, pipe 24 is disconnected from pipe 23, and the supply of uid pressure to cylinder 9 is therefore cut off, and since valve V1 is energized, cylinder 9 is connected with atmosphere. The braking bars are therefore held in their ineffective or nonbraking positions by gravity. The contact :Z6-26a of each of the pressure responsive devices P is closed, and the contact 26-26b of each of these devices is open.

In explaining the operation of the apparatus as a whole, I will iirst assume that the operator Wishes to make a comparatively light brake application. To do this, he moves lever L from its p1 to its p2 position, thereby opening contact 271 of lever L and closing contact 272. The opening of the contact 271 interrupts the circuit which was previously closed for valve V1 at this contact, and valve Vl therefore now becomes deenergized, and disconnects pipe 17 from port 22 and connects this pipe with the pipe 23. The closing of contact 272 completes a circuit for a valve V2, and current flows from battery B through wires 28, 29, 30 and 31, contact 272 of lever L, line wire 38, contact 2-26EL of pressure responsive device P204", wires 39, 40, 4l and 42, winding 20 of valve V2, and line wire 37 back tobattery B. Valve V2 therefore becomes energized and connects pipe 24 with pipe 23, so that fluid at full line pressure is now supplied to the upper end of cylinder 9, thus causing the braking bars to move to their effective or braking positions. As soon as the fluid in the upper end of cylinder 9 reaches twenty pounds per square inch, Contact 26--26a of pressure responsive device P20-3 will open and will interrupt the circuit just traced for valve V2. Valve V2 will then become deenergized and will cut off the supply of fluid to thexupper end of the cylinder until the pressure in the motor again decreases below twenty pounds per square inch, at which time valve V2 will again become energized and will again admit fluid to the cylinder. If the fluid in the motor now increases to a pressure of thirty pounds per square inch for any reason, contact 26--26lo of pressure responsive device P20-30 will become closed and will complete a circuit for valve V1 which passes from battery B through wires 28, 29, 30 and 31, contact 272 of lever L, line wire 33, contact 2-26b of pressure responsive device P20-30, wires 34, 35 and 36, winding 20 of valve V1, and line wire 37 back to battery B. Valve V3 will therefore become energized, and will vent fluid pressure from cylinder 9 until the pressure again decreases to thirty pounds per square inch and permits contact 265-26b to open. It will be seen, therefore, that when lever L occupies its p2 position, the braking bars will be held in their braking positions by a pressure of between twenty and thirty pounds per square inch.

If the operator desires to make a more powerful brake application, he moves lever L to its p3 position in which contact 273 is closed. Under these conditions, valve V1 will be deenergized, and valve V2 will become energized over a circuit which passes from battery B through wires 23, 29 and 30, contact 273 of lever L, line wire 43, contact 262621 ofpressure responsive device 1245-55, wires 40, 41 and 42, winding 20 of valve V2, and line wire 37 back to battery B. Fluid pressure will therefore now be admitted to the upper end of cylinder 9 until the pressure of thefluid in the cylinder increases to forty-five pounds per square inch, at which time contact 26--26a of pressure llcU responsive device F15-55 `will open and will deenergize valve V2. If the pressure in the upper end of cylinder 9 now increases to fifty-five pounds per square inch, contact 26--26b of pressure responsive device F15-55 will become closed and will complete ano-ther circuit for valve V1, this latter circuit passing from battery B, through wires 28, 29 and 30, contact 273 of lever L, line wire 43, contact 26-25b of pressure responsive device P4525, wires 35 and 36, winding 20 of valve V1, and line wire 37 back to battery B. Valve V1 will therefore become energized and will exhaust fluid from the upper end of cylinder 9 until the pressure decreases to that at which contact 26-26b of pressure responsive device P4555 opens. It will be apparent, therefore, that when lever L occupies its p3 position, the braking bars will be held in their braking positions by a pressure of between forty-five and fifty-five pounds per square inch.

If the operator moves lever L to its p1 position, valve V2 will then become energized over a circuit which passes from battery B through Wires 28 and 29, contact 271 of lever L, line wire 44, contact 26--26a of pressure responsive device P1040, Wires 41 and 42, winding 20 of valve V2 and line wire 37 back to battery B. Under these conditions, fluid will be supplied to the upper end of cylinder 9 until the pressure in the cylinder reaches seventy pounds per square inch, which is the pressure at which contact 26-26n of pressure responsive device P80 opens. If the pressure in cylinder 9 now increases to eighty pounds per square inch, contact 26--26b of pressure responsive device P7"-80 will become closed, and will complete still another circuit for valve V1. This latter circuit for valve V1 may be traced from battery B through wires 28 and 29, contact 274 of lever L, line wire 44, contact 26-260 of pressure responsive device P10-20, wire 36, winding 2O of valve V1, and line Wire 37 back to battery B. Valve V1 will therefore become energized until the pressure in the upper end of cylinder 9 again decreases to eighty pounds per square inch. It will be seen, therefore, that when lever L is moved to its p4 position, cylinder 9 is supplied with iiuid at a pressure of between seventy and eighty pounds per square inch, so that the braking bars exert a corresponding braking force.

If the operator desires to cause the braking bars to exert their maximum braking force, he moves lever L to its p5 position. Under these conditions, valve V2 becomes energized and subsequently remains energized over a circuit which passes from battery B through wire 28, contact 275 of lever L, line wire 45, wire 42, Winding 20 of valve V2, and line wire 37 back to battery B. It will be apparent, therefore, that, under these conditions, the braking bars will be held in their braking positions by fluid at full line pressure.

It should be observed that if the operator moves the lever L from a position corresponding to a higher braking force to a position corresponding to a lower braking force, the apparatus immediately and automatically reduces the braking pressure to a value corresponding to the new position of the lever in a manner which will .be

apparent from the drawings without tracing the sequence of operation in detail.

When lever L occupies any one of its p2, p2, p4, or p5 positions, so that the braking bars occupy their braking positions, and the operator wishes to restore the braking bars to their non-braking positions in which they are illustrated in the drawings, he will restore lever L to itsip1 or "ofl` position. Whenhe-does this, all circuits previously tracedfor valve V2 will be interrupted, and

the circuit previously described for valve V1 including contact 271 of lever L will become closed. Valve V2 Awill therefore become deenergized and valve V1 will become energized. As a result, the supply of fiuid pressure to the upper end of cylinder 9 will be cut off and the fluid which was previously supplied to this end of the cylinder will be vented to atmosphere. The braking bars will therefore move under the influence of gravity, to their ineffective or vnon-braking positions. When the brakingbars reach their non-braking positions, all parts are restored to the positions in which they. are shown in the drawings.

One advantage of the apparatus shown in Fig. l is that the short-circuiting of the contacts of one of the pressure responsive devices, as by a condensation of moisture on the contacts due to unfavorable weather conditions, will not, under any conditions, cause a direct fiow of iiuid from the source to atmosphere, as has heretofore been possible. For, if one of the pressure responsive devices becomes short-circuited, the valves V1 and V2 will become simultaneously energized in a manner which will be readily understood from an inspection of the drawings, but due to the fact that it is necessary for valve V1 to be deenergized when valve V2 is energized before fluid can be supplied to the motor from the source, valve V1 will act, under these conditions, to prevent the flow of iiuid from the source past this valve. It will be seen, therefore, that with the apparatus shown in Fig. 1 there can be no waste of fluid due to improper operation of the valves under any conditions.

Referring now to Fig. 2, as here shown, the pipe 23, instead of being connected with the pipe 17 through the valve V1, as shown in Fig. 1, is connected directly with the pipe 17, so that uid pressure from the pipe 24 will be supplied to cylinder 9 whenever valve V2 is energized regardless of whether Valve V1 is then energized or deenergized, this being the usual arrangement of valves commonly employed for controlling the supply of iiuid to, and exhaust of nid from, a fluid pressure motor of the type shown. Furthermore, as shown in Fig. 2, the circuits for controllingthe valves V1 and V2 have been modified somewhat, and rectiiiers have been included in some of these circuits in order to decrease the number of line wires between the control point and the braking apparatus, and to prevent improper operation of the valves in the event that rthe contacts of one of the pressure responsive devices become short-circuited, as by condensation of moisture on the contacts, when lever L occupies its p1 or off position.

The operation of the apparatus shown in Fig. 2 is as follows: When lever L occupies its p1 or off position, valve V2 is deenergized so that the supply of fluid pressure to motor M is cut oif, and valve vV1 is energized over a circuit which passes from battery B through wires 48, 30, 3l and 32,

contact 271 of lever L, line wire 33, wire 49, winding 20 of valve V1, and line wire 37 back to battery B. Since valve V1 is energized, cylinder 9 of motor M is connected with atmosphere through port 22, and the braking bars are therefore held in their non-braking positions by gravity. Furthermore, since cylinder 9 is vented to atmosphere, the contacts 26---26a of the pressure responsive devices P are all closed, and the contacts `26-26b are allr open.

If nowlever L is moved to its plposition, valve Vl will become deenergized, and valve V2 will become energized over a circuit which passesfrom battery B through wires 48, 30 and 3l, contact 272 of lever L, line wire 38, contact 26--26a of pressure responsive device P20-30, wires 39, 40 and 50, winding 2i) of valve V2, and line wire 37 back to battery B. The deenergiaation of valve V1 will cut off the supply of fluid pressure to cylinder 9 of motor lVI, while the energization or" valve V2 will connect the cylinder with the pipe 24, so that fluid pressure will then be suppliedV to the cylinder, thus moving the braking bars of the car retarder to their braking positions. When the pressure of the fluid in cylinder 9 increases to twenty pounds per square inch, contact 26-26a of pressure responsive device P20-30 will open and will deenergize valve V2, and if the pressure in the cylinder increases to thirty pounds per square inch, contact 26-26b of pressure responsive device P20-3 will become closed and will complete a circuit for valve V1, which circuit may be traced from battery B through wires 48, 30 and 3l, contact 272 of lever L, line wire 38, contact 26-26b of pressure responsive device P20-30, Wires 34 and 35, an asymmetric unit 5l in its low resistance direction, wire 49, winding 20 of valve V1, and Wire 37 back to battery B. Valve V1 will therefore become energized, and will vent luid from cylinder 9 to atmosphere until the pressure of the fluid in the cylinder decreases suliiciently to cause contact 26-26b of pressure responsive device P20-3 to open and deenergize valve V1. It will be seen, therefore, that with the apparatus shown in Fig. 2, when lever L is moved to its p2 position, the braking bars will be held in their braking positions by a pressure of between twenty and thirty pounds per square inch, in the same manner as with the apparatus shown in Fig. l.

If lever L is moved to its p3 position, valve V2 will become energized over a circuit which passes from battery B through wires 48 and 30, contact 273 of lever L, line wire 43, contact 26-26'-L of pressure responsive device F15-55, wires 40 and 50, winding 20 of valve V2, and line wire 37 back to battery B. Valve V2 will now remain energized until the pressure of the iluid in cylinder 9 increases to forty-ve pounds per square inch, at which time contact 26--265 of pressure responsive device P25-55 will open and will deenergize valve V2. If the pressure of the fluid in cylinder 9 increases to fifty-nve pounds per square inch under these conditions, valve V1 will become energized over a circuit which passes from battery B through Wires 48 and 80, contact 273 of lever L, line wire 43, contact 26--26b of pressure responsive device P45v55, wire 35, asymmetric unit 5l in its low resistance direction, wire 49, winding 20 of valve V1, and line wire 37 back to battery B. It will be seen, therefore, that when lever L occupies its p3 position the braking bars will be held in their braking positions by a pressure of between fortyve and nity-ve pounds per square inch.

If lever L is moved to its p4 position, valve V2 will become energized and will remain energized until the pressure of the fluid in the motor increases to seventy pounds per square inch, the current for the valve under these conditions passing from battery B through wire 48, contact 274 of lever L, line wire 44, contact 26-252t of pressure responsive device P20-80, wire 50, winding 20 of vaive V2 and line wire-37 back to battery B. If the pressure of the fluid in the motor now increases to eighty pounds per square inch, valve V1 will become energized over ar circuit which passes from battery B through wire 48, contact 274 of lever L, line wire 44, contact 26---26b of pressure responsive device P'O-, asymmetric unit 51 in its low resistance direction, wire 49, winding 20 of valve V1, and wire 37 back to battery B. It follows that when lever L occupies its p4 position, the braking bars will be held in their braking positions by a pressure of between seventy and eighty pounds per square inch.

If lever L is moved to its p5 position, valve V2 will become energized and will subsequently remain energized by virtue of a circuit which passes from a battery C through line wire 37, winding 20 of valve V2, an asymmetric unit 52 in its low resistance direction, line wire 44, and contact 275 of lever L back to battery C. Under these conditions, therefore, the braking bars will be held in their braking positions by uid at full line pressure.

In order to restore the apparatus from its closed or effective position to its open or ineffective position, the operator moves lever L to its p1 or off position, in which position it is illustrated in the drawings. All circuits for valve V2 are then interrupted, and the circuit previously traced for valve Vl then becomes closed at contact 271 of lever L. Valve V2 therefore becomes deenergized and cuts off the supply of nuid pressure to motor M, while valve V1 becomes energized and Vents the iluid which was previously supplied to the motor to atmosphere. The braking bars therefore then return to their braking positions under the influence of gravity. When the braking bars reach their braking positions, the parts are all restored to the positions in which they are illustrated in the drawings.

It should be pointed out that, with the apparatus constructed as shown in Fig. 2, if the asymmetric unit 5l were omitted and the contacts of one of the pressure responsive devices became short-circuited, as by a drop of water,

when lever L occupies its p1 or off position, the valves V1 and V2 would then both become energized, and there would then be a continuous eX- haust of fluid pressure from the source to atmosphere. The asymmetric unit 51, however, prevents this from happening because it prevents the flow of current from the line wire 33 to the pressure responsive devices, and hence to the valve V2, under these conditions. The asymmetric unit 52 is provided to permit selective con- 125 trol of the valves V1 and V2 over a single pair of line wires, by reversing the polarity of the current supplied to the line wires.

Although I have herein shown and described only two forms of railway braking apparatus em- 13?' bodying my invention, it is understood that various changes and modications may be made therein within the scope of the appended claims without departing from the spirit and scope of `rst contact is closed for normally supplying fluid pressure to said motor, a second contact which becomes closed when the pressure of the fluid in said motor increases to a pressure which is somewhat higher than the pressure at which said first contact opens, means effective when said second contact is closed for exhausting fluid from said motor, and means effective under certain conditions if both of said contacts became simultaneously closed due to a short circuit for preventing fluid from being supplied to said motor or exhausted to atmosphere.

2. Railway braking apparatus comprising a braking bar located in the trackway beside a track rail, a fluid pressure motor for moving said braking bar toward the track rail into a braking position in which it will engage a part of a car to retard the speed of the car, a first Contact which becomes opened when the pressure of the fluid in said motor increases to a predetermined pressure and a second contact which becomes closed when the pressure of the fiuid in said motor increases to a pressure which is somewhat higher than the pressure at which said first contact opens, a manually operable lever having an off and an on position, means effective when said lever occupies its off position for normally connecting said motor with atmosphere, means effective when said lever occupies its on position and said first contact is closed for normally connecting said motor with a source of fluid pressure, means effective when said lever occupies its on position and said second contact is closed for normally connecting said motor with atmosphere, and means effective if said two contacts become short-circuited when said lever occupies its olf position for preventing fluid pressure from being supplied to said motor or exhausted to atmosphere.

3. Railway braking apparatus comprising a braking bar movable toward and away from a track rail into braking and non-braking positions, and biased to a non-braking position, a uid pressure motor for moving said braking bar to its braking position, a pressure responsive device subjected to the pressure of the fluid in said motor and provided with a first contact which becomes opened when the pressure of the fiuid in said motor increases to a predetermined pressure and with a secondV contact which becomes closed when the pressure of the fluid in said motor increases to a pressure which is somewhat higher than the pressure at which said first contact opens, a source of fluid pressure, means controlled in part by said first contact for connecting said motor with said source of fluid pressure, means controlled in part by said second contact for connecting said motor with atmosphere, and means at times effective in the event that said two contacts become simultaneously closed due to a short circuit for preventing said source from becoming connected with atmosphere.

4, Railway braking apparatus comprising a braking bar movable toward and away from a track rail into braking and non-braking positions, and biased to a non-brakingposition, a fiuid pressure motor for moving said braking bar to its braking position, a pressure responsive device subjected to the pressure of the fiuid in said motor and provided with a first contact which becomes opened when the pressure of the fluid in said motor increases to a predetermined pressure and with a second contact which becomes closed when the pressure of the fluid in said motor increases to a pressure which is somewhat higher than the pressure at which said first contact opens, manually controlled means effective when said first contact is closed for the event that both of said contacts become simultaneously closed due to a short circuit for preventing said source from becoming connected with atmosphere.

5. Railway braking apparatus comprising a. braking bar movable toward and away from a track rail into braking and non-braking positions and biased to its non-braking position, a fluid pressure motor for moving said braking bar to its braking position, a first and a second magnet valve, a source of fiuid pressure, means including said two magnet valves and effective when and only when said first valve is energized and said second valve is deenergized for connecting said motor with said source of fiuid pressure, means including said second valve and effective only when said second valve is energized for connecting said motor with atmosphere, a pressure responsive device provided with a first contact which becomes opened when the pressurerof the iiuid in said motor increases to a predetermined value and with a second contact which becomes closed when the pressure of the fluid in said motor increases to a value which is somewhat higher than the value at which said first contact becomes opened, a circuit for said first valve including said first contact, and a circuit for said second valve including said second contact.

6. Railway braking apparatus comprising a. braking bar movable toward and away from a track rail into braking and non-braking positions and biased to its non-braking position, a iiuid pressure motor for moving said braking bar to its braking position, a flrst and a second magnet valve, a source of fiuid pressure, means including said two magnet valves and effective when and only when said first valve is energized and said second valve is deenergized for connecting said motor with said source of fluid pressure, means including said second valve and effective only when said second valve is energized for connecting said motor with atmosphere, aA pressure responsive device provided with a first contact which becomes opened when the pressure of the fluid in said motor increases to a predetermined value and with a second contact which becomes closed when the pressure of the fluid in said motor increases to a value which is somewhat higher than the value at which said first contact becomes opened, a manually controlled lever, a circuit for said first valve controlled by said lever and including said first contact and a circuit for said second valve controlled by said lever and including said second contact.

7. Railway braking apparatus comprising a braking bar movable toward and away from a track rail into braking and non-braking positions and biased to its non-braking position, a fiuid pressure motor for moving said braking bar to its braking position, a first and a second magnet valve, a source of fluid pressure, means including said two magnet valves and effective when and only when said first valve is energized and said second valve is deenergized for connecting said motor with said source of fiuid pressure, means including said second valve and effective only when said second valve is energized for connecting said motor with atmosphere, a series of pressure responsive devices, a first series of contacts fill@ one controlled by each oi.' said pressure responsive devices in such manner that said contacts will become successively opened as the pressure in said motor increases, a second series of contacts one controlled by each of said pressure responsive devices and each arranged to become closed when the pressure of the fluid in said motor increases to a pressure which is somewhat higher than the pressure at which the contact of the first series which is controlled by the same pressure responsive device opens, a plurality of circuits for said first valve each controlled by a different contact of said rst series of contacts, and a plue rality of circuits for said second valve each controlled by a different contact of said second series.

8. Railway braking apparatus comprising a braking bar movable toward and away from a track rail into braking and non-braking positions and biased to its non-braking position, a iiuid pressure motor for moving said braking bar to its braking position, a rst and a second magnet valve, a source of iiuid pressure, means including said two magnet valves and eective when and only when said first valve is energized and said second valve is deenergized for connecting said motor with said source of iiuid pressure, means including said second valve and effective only when said second valve is energized for connecting said motor with atmosphere, a first series of pressureresponsive contacts arranged to become successively opened as the pressure in said motor increases, a second series of pressure reponsive contacts one for eachcontact of the first series and each arranged to become closed at a pressure which is somewhat higher than the pressure at which the corresponding contact of the iirst series opens, a manually operable lever provided with a plurality of contacts which are selectively operated in response to movement of said lever to different positions, a plurality of circuits for said rst valve each including a different contact of said lever and a different contact of said iirst series of contacts, and a plurality of circuits for said second valve each including a different contact of said lever and a different contact of said second series of contacts.

9. Railway braking apparatus comprising a braking bar located in the trackway beside a track rail, a fluid pressure motor for movingrsaid braking bar toward the track rail into a braking position in which it will engage a part of a car to retard the speed of the car, a first magnet valve effective when energized for connecting said motor with a source of iiuid pressure, a second magnet valve effective when energized for connecting said motor with atmosphere, a lever having an off and an on position and provided with a first contact which is closed when said lever occupies its off position and with a second contact which is closed when said lever occupies its on position, a device responsive to the pressure of the iiuid in said motor and provided with a normally closed contact which becomes opened when j the pressure of the fluid in said motor increases to said asymmetric unit, and a iirst circuit for said flrst valve including said second contact of said lever and said normally closed contact.

10. Railway braking apparatus comprising a braking bar located in the trackway beside a track rail, a fluid pressure motor for moving said braking bar toward the track rail into a braking position in which it will engage a part of a car to retard the speed of the car, a rst magnet valve effective when energized for connecting said motor with a source of fluid pressure, a second magnet valve effective when energized for connecting said motor with atmosphere, a lever having two positions and provided with a first contact which is closed in the one position and a second contact which is closed in the other position, a device responsive to the pressure of the fluid in said motor and provided with a normally closed contact which becomes opened when the pressure of the fluid in said motor increases to a predetermined value and with a normally open contact which becomes closed when the pressure of the fluid in said motor increases to a pressure which is somewhat higher than the pressure at which said first contact opens, two asymmetric units, two sources of electromotive force, a first circuit for said rst valve including one of said sources of electromotive force, said normally closed contact, and said one contact of said lever; a first circuit for said second valve including said one source of electro- '.1

11. Railway braking apparatus comprising a i braking bar located in the trackway beside a track rail, a fluid pressure motor for moving said braking bar toward the track rail into a braking position in which it will engage a part of a car to retard the speed of the car, a first magnet i valve effective when energized for connecting said motor with a source of fluid pressure, a second magnet valve effective when energized for connecting said motor with atmosphere, two line Wires, means for reversibly supplying current to said line wires, a device responsive to the pressure of the fluid in said motor and provided with a normally closed contact which becomes opened when the pressure of the fluid in said motor increases to a predetermined pressure and with a normally open contact which becomes closed when the pressure of the fluid in said motor inlili@ creases to a pressure which is somewhat higher than the pressure at which said iirst contact opens, two asymmetric units, means including one of said asymmetric units for connecting said first magnet valve with said line wires when said .line wires are supplied with current of one polarity, means including said normally open contact and the remaining asymmetric unit for connecting L1 said second magnet valve with said line wires when said line wires are supplied with current of the other polarity, and means including said normally closed contact for connecting said first magnet valve with said line wires when said line wires are supplied with current of said other polarity, said two asymmetric units being disposed in opposite directions with respect to said line Wires.

HERBERT L. BONE. 

